Hello, I'm sorry you're having this issue! I'm not too sure what's causing this to happen, it appears you've set up the parameters correctly and have the video files in the correct folder.
Is there perhaps another plugin which might be conflicting with this one? When do you get a black screen? Immediately upon boot? Does it say anything in console?
If you're still having this issue then I'll need more information to understand why it's happening and I'll be happy to help solve it.
Thank you and good luck!